feat(autorenewal): implement automatic subscription renewal system

repositories/subscriptions.py

@@ -1,4 +1,4 @@
-from datetime import datetime
+from datetime import datetime, timezone
 
 from sqlalchemy import select, update
 from sqlalchemy.ext.asyncio import AsyncSession
@@ -7,6 +7,24 @@ from db.models.subscriptions import Subscription, SubscriptionStatus
 
 
 class SubscriptionRepository:
+    async def get_subscriptions_for_autorenewal(
+        self, session: AsyncSession, *, days_before_expiry: int = 1
+    ) -> list[Subscription]:
+        from datetime import timedelta
+
+        threshold = datetime.now(timezone.utc) + timedelta(days=days_before_expiry)
+        stmt = (
+            select(Subscription)
+            .where(
+                Subscription.autorenew == True,
+                Subscription.status == SubscriptionStatus.ACTIVE,
+                Subscription.end_date <= threshold,
+            )
+            .with_for_update()
+        )
+        result = await session.execute(stmt)
+        return list(result.scalars().all())
+
     async def get_subscription_by_user_id(
         self, session: AsyncSession, user_id: int
     ) -> Subscription | None:

repositories/users.py

@@ -112,7 +112,7 @@ class UserRepository:
             amount=amount,
             tx_type=tx_type,
             balance_before=user.balance,
-            balance_after=user.balance + amount,
+            balance_after=user.balance - amount,
             description=description,
             created_at=created_at,
         )